class_docstr: Give a sentiment intensity score to sentences.
code: def _but_check(self, words_and_emoticons, sentiments):
      words_and_emoticons = [w_e.lower() for w_e in words_and_emoticons]
      but = {"but"} & set(words_and_emoticons)
      if but:
          bi = words_and_emoticons.index(next(iter(but)))
          for sidx, sentiment in enumerate(sentiments):
              if sidx < bi:
                  sentiments[sidx] = sentiment * 0.5
              elif sidx > bi:
                  sentiments[sidx] = sentiment * 1.5
      return sentiments
  
imports: import math
  import re
  import string
  from itertools import product
  import nltk.data
  from nltk.util import pairwise
label_desc: Use image node_id 6 for calling the SentimentIntensityAnalyzer obj's underlying member method code with example usage: obj._but_check(words_and_emoticons, sentiments) and returns: sentiments